How far? How fast?
Energy changes in chemical reactions
reactions between methane and oxygen
methane + oxygen -> carbon dioxide + water
Rates of reaction
endothermic process and exothermic process
the reaction between nitrogen and oxygen
nitrogen + oxygen -> nitrogen monoxide
bond energy
CH4(g) + 20 2 (g) -> CO2(g) +2H2O(g)
bond making and bond breaking
factors affecting the rate of reaction
the surface area of any solid reactants
the concentration of the reactants
the temperature at which the reaction is carried out
the use of a catalyst
in influence of light on some reactions.
speed of a reaction increases when the surface area of a solid reactant is increased
Catalysts
hydrogen peroxide -> water + oxygen
catalytic converters
enzymes (biological catalysts)
proteins, temperature-sensitive
collision theory
when a solid is broken, there are more places where collisions can take place. -> more reactions taking place.
Photochemical reactions
photosynthesis
process where life traps energy when sunlight falls on leaves containing the green pigment chlorophyll
photography
2AgBr -sunlight-> 2Ag + Br2
Reversible reactions and chemical equilibria
reaction between nitrogen and hydrogen to produce ammonia: N2(g) + 3H2 <=> 2NH3(g)
CuSO4.5H2O(s) -heat-> CuSO4(s) + 5H2O(g)
reversible reaction